Preparing a textured yarn package, for dyeing

ABSTRACT

A textured yarn is tensioned sufficiently to stabilize the yarn but insufficiently to remove the texture and is wound at a low tension to form a soft package on a collapsible package support. The yarn package is then dyed at an elevated temperature.

United States Patent Koslowski July 1, 1975 [54] PREPARING A TEXTURED YARN 3,425,! 10 2/1969 Willis 28/75 WT E 3,543,358 l2/l970 Breen et al. 1 28/l.4 X PACKAGE FOR DY ING 3,703,753 ll/l972 Binford v. 28/72.l2 [75) Inventor: Manfred Gunter Koslowski,

Vorhelm/Kreis Beckum, Germany [73] Assignee: E. I. du Pont de Nemours & Primary Examiner-L0uis K. Rimrodt Company, Wilmington, Del.

[22] Filed: Dec. 14, 1973 2l A l. N 424,811 1 pp 0 57 ABSTRACT [52] US. Cl 28/72.]2; 28/75 WT; 57/l57 FV i [5|] Int. Cl. D02g 1/16 A textured yam tensloned sufficlently to subdue [58] Field of semtch H 28 21, 72,12 75 the yarn but insulficiently to remove the texture and is 57134 157 wound at a low tension to form a soft package on a collapsible package support. The yarn package is then 56] References cued dyed at an elevated temperature.

UNITED STATES PATENTS 2,852,906 9/1958 Breen 57/157 F 2 Claims, 5 Drawing Figures L0. lEISlOI IIID OVEllFEED USZOZO SHEET I PREPARING A TEXTURED YARN PACKAGE. FOR DYEING BACKGROUND OF THE INVENTION The present invention relates to an improved process of preparing and dyeing a soft package of a relatively inelastic textured continuous multifilament or spun synthetic polymeric yarn which shrinks substantially under the heating conditions encountered following texturing.

A process for texturing continuous filament yarn or staple yarn by means of a turbulent air jet is known from Breen. U.S. Pat. No. 2.852.906. In the case of continuous multifilament yarn. the turbulent jet forms each filament occasionally into a loop and entangles the filaments to bind the loops into a yarn structure consisting of a more or less compact entangled core. crunodal filament loops extending out from the surface of the core and some filament loops buried within the core structure. The yarn is fed into the texturing jet at a rate greater than the take-away speed to provide the excess filament length required for forming loops and a high degree of entanglement.

After the textured yarn is taken away from the jet at low tension. it must be stretched tostabiiiie the structure. Otherwise. the yarn will stretch when it is woven or knitted at tensions higher than exist in the jet portion of the texturing process and will usually do so nonuniformly because of nonuniform cyclical tensions in weaving and knitting operations. resulting in irregular fabric appearance. Therefore. it is necessary to apply a tension to the yarn greater than that which the yarn will receive in subsequent winding and fabric making operations. Normally. this is done by winding the yarn on a package at sufficient tension tostabilize the yarn and to provide a firm or hard package of minimum volume which can be handled and shipped without damage. However. such hard packages are not suitable for package dyeing because they are so tightly wound that it is difficult for liquid dye to uniformly penetrate the package. A soft package of yarn. on the other hand. is easily penetrated with liquid dye and is desired for package dyeing of yarn. This has normally been accomplished in the past by rewinding the yarn onto a collapsible core under low winding tension to form a soft package. This additional step of rewinding is costly and time consuming.

The soft yarn packages are placed in a dye bath and dyed. They are normally stacked in axial alignment on a dye tank loading rod and compressed axially to eliminate spaces between the ends of adjacent yarn packages. Dye is then circulated through the dye tank loading rods which are normally perforated tubes of smaller diameter than the inside diameter of the yarn packages and the dye temperature is raised at a controlled rate. A typical dye heat cycle for a yarn which has previously been autoclaved. heats the bath from 60 to 110C. at a rate of 4C. per minute and from to IC. at a rate of 2C. per minute. The critical dyeing temperature for such yarn is "0 to l30C.

After dyeing. the yarn is rewound onto a cone to provide a finished package of textured and dyed yarn. During winding. the yarn is lubricated to improve its knitting properties.

SUMMARY OF THE INVENTION It has now been found that yarn may be air textured.

stabilized and dyed uniformly by a process comprising the continuous steps of (a) overfeeding the yarn through an air jet texturing process as described in Breen U.S. Pat. No. 2.852.906 (b) stretching the yarn by an amount sufficient to stabilize the yarn but insufficient to eliminate texture-giving loops (c) winding the yarn under relatively low constant tension onto a radially and axially collapsible core at a tension of less than about 0.04 gram per denier to form a soft package. Thereafter. the package of yarn is dyed at elevated temperature to shrink the yarn and dye it simultaneously. The stretching is preferably under a tension higher than the tension which the finished yarn receives in subsequent rewinding, knitting or weaving operations and is preferably by an amount of 5-20 percent. The stretching may advantageously be performed by progressing the yarn from the smaller step of a stepped roll which controls the take-away speed of the yarn from the texturing jet and progressing it to larger diameter step ofa diameter'greater by 5 to 20 percent than the smaller diameter, the yarn being progressed from one step to another by the use of guides or freely rotating separator rolls. The degree of stretch, however.

must usually be less than the degree of overfeed through the texturing jet. in order to retain a substantial degree of loops. When the feed yarn to the texturing operation is fully drawn. the overfeed minus the stretch is preferably at least 10% but is dependent on the material used or the degree of texture desired. When undrawn or partially drawn feed yarn is used. the degree of stretch may exceed the overfeed while retaining bulk-giving loops.

This process significantly reduces the steps required in texturing and dyeing yarn, and thereforereduces costi Waste losses also decline. The use of a stepped roll for stretching the yarn prior to winding a soft package permits use of texturing machines havingonly one powered drive between texturing and windup.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 4 is a perspective view of a dye loading rod of FIG. 3.

FIG. 5 is an end view of the dye loading rod of FIG. 4- l DETAILED DESCRIPTION OF THE-PREFERRED EMBODIMENT Referring to FIG. l. yarn 4 is taken from feed yarn package 2 mounted on platform 3 and passes through tension and stop motion device 5 to feed roll 6 where it may be wrapped several times with the aid of guide 7 to prevent slippage. It then passes to texturing jet 10 which is supplied with compressed air through pipe 8 from a source not shown. Optionally. the yarn may pass through a tank 9 where water or other treating liquid is applied to the yarn before entering texturing jet 10. It may be preferable to place an enclosure around bath 9 and jet T0 to collect droplets of liquid which escape from or are blown off the yarn. The textured yarn then contacts driven roll surface 24 operating at surface speed less than that of feed roll 6. The yarn then passes to another roll surface 25 operating at a surface speed faster than roll surface 24. Roll surfaces 24 and 25 may be the smaller and larger diameter steps on a single driven stepped roll I7. Multiple wraps to reduce slippage may be provided by grooved guides I5 and 16 or equivalent means. The yarn then passes over one or more guides 18 to traverse guide I9 which winds the yarn as soft package 21 on core 20. which is preferably a commercially-available dye spring. collapsible both axially and radially. Core 20 is mounted on a chuck (not shown) which holds core 20 at or near its maximum diameter while package 21 is being wound. Yarn is wound at a tension considerably lower than that encountered during the stretching operation following texturing.

FIG. 2 shows details of a preferred texturing device. Texturing jet I0 may preferably be a device of Lubach. U.S. Pat. No. 3,545,057 in which compressed air flowing into the device through pipe 8 encounters a severe restriction of such as hole 13 which directs a concentrated stream of high velocity fluid onto yarn 4 as it emerges from yarn guiding outlet 1!. The turbulent air and the yarn then pass together through the throat of venturi I2. It may also be preferable to employ floating baffle plate I4 which is described in more detail in copending application Koslowski U.S. Ser. No. 315,563 filed Dec. I5, I972. Baffle 14 is free to pivot about hinge pin 23 which is supported by bracket 22 which may be clamped around the periphery of texturing jet I0 and may be adjustable along the length of the jet. Textured yarn leaves jet device I0 at approximately right angles to its direction of travel through the jet. Use of this preferred texturing device not only allows satisfactory texturing at higher speed than prior devices but produces unusually uniform tension in the yarn between the texturing jet and roll I7 which in turn allows more uniform stretching before winding.

FIG. 3 shows equipment suitable for dyeing the soft packages. Yarn packages indicated by 27 and 28 are stacked axially on dye loading rod 29 shown in greater detail in FIGS. 4 and 5. The stack of packages is then compressed axially so that the ends of the dye springs compress axially and allow the edges of adjacent packages to contact each other so as to form a uniform column of softly packed yarn. The rods are in a conventional yarn dye tank 26. The lid of dye tank 26 is then closed and dye is pumped from reservoir 30 through conduit 31. Pump 32 forces dye from reservoir 30 through conduits 31 and 33 into dye tank 26, and thence into conduit 34 having vertical pipes which connect with the center of packages 27 and 28. Dye is usually at some elevated temperature such as 60C. when it is first introduced into the dye tank 26. Thereafter, hot water or steam is introduced through conduit 36 from a reservoir (not shown), is circulated through heating coil 35 and is removed through conduit 37. As the temperature rises, the yarn shrinks and the dye spring collapses radially to maintain a soft package of relatively uniform density having sufficient porosity to allow easy and uniform flow of dye through the package.

FIGS. 4 and 5 show a preferred dye loading rod in greater detail. Conventional dye equipment generally employs a perforated tube having an outer diameter slightly smaller than the minimum inner diameter of a fully shrunk yarn package. When yarn packages of unshrunk yarn having a substantially larger internal diameter than the outside diameter of the dye rod are stacked on such a rod. the packages may be misaligned with each other by an amount equal to the difference between the inner diameter of the unshrunk package and the outer diameter of the dye rod. Such misalignment causes uneven compression of yarn at both the inside and outside of packages and results in uneven dyeing. The preferred rod of FIGS. 4 and 5 consists of a longitudinally extending main member 38 having a cross section in the shape of a cross intersecting at angles and having arms of equal length. The point of intersection 39 is the longitudinal axis of the rod. De pendent from member 38 are at least two longitudinally extending members 40 and 41 that are shown in the shape of a round bar supported on springs 42 which extend in a radial direction from the longitudinal axis 39 of the rod. When the springs are in expanded position holding rods 40 and 41 at full extension, the distance between the longitudinal axis 39 of the main member and the outermost point of either rod 40 or 41 at full extension, the distance between the longitudinal axis 39 of the main member and the outermost point of either rod 40 or 41 indicated as L, in the drawings is chosen to coincide with the inside radius of the collapsible core in its initial uncollapsed state. This ensures proper axial alignment of the packages. As the yarn shrinks radially. springs 42 compress. The lengths of the arms of the main members indicated by L; in the drawing should be slightly smaller than the inside radius of a core after full shrinkage.

The use of the terms hard pack" and soft pack" and their derivatives are of course relative. As stated before, a hard packed core of yarn is so tightly wound that it is difficult or impractical to penetrate with a liquid dye uniformly. A soft package of yarn. on the other hand, is easily penetrated with liquid dye uniformly. In general, a Shore hardness less than 40 is considered a soft package and a Shore hardness over 40 is considered a hard package. Shore hardness is a measure of package density as measured with a Durometer, an in strument for testing package density, manufactured by the Shore Instrument and Manufacturing Company, Inc.

Since the relative humidity of the room in which winding is performed affects the tension of the yarn as wound on the package, it is important to control the relative humidity of such room within a range of about fi% RH. That is to say, the relative humidity should not vary by more than this amount from time to time during the winding operations, and no winding machine should differ from any other running at the same operating conditions by more than this amount.

Although the following example concerns polyester yarn, similar conditions may be employed for texturing nylon, polypropylene or other yarns of commercial importance. In general, yarns having higher shrinkage during heating should be wound on core 20 at lower tensions. Whereas. a single end of denier yarn is exemplified, multiple ends of the same or different yarns may be fed at the same or different speeds to the texturing jet.

EXAMPLE Dacron polyester yarn of 150 denier (167 d-tex) having 68 filaments designated as R-l0. Type 56, is placed on a device of FIG. I in which feed roll 6 is operating at 482 yards per minute (440 meters per minute). The yarn passes through water bath 9 into texturing jet 10 shown in FIG. 2 in which hole 13 is 2.78 millimeters. yarn hole 11 is 0.51 millimeter and renturi 12 is 1.78 millimeters diameter. Air pressure is 118 lbs/sq. in. gauge (8 atmospheres). Baffle plate 14 is approximately 68 millimeters from hinge point 23 to the end and is 40 millimeters wide. Yarn passes from the jet at low uniform tension to a smaller diameter step of roll 17 which is operating at 340 yards/min. (311 meters/- min.) with a resultant o erfeed between feed roll 6 and roll surface 24 of 42 percent. Roll surface 25 is operating at 398 yards per minute (364 meters per min.) thus stretching the yarn between roll surfaces 24 and 25 by 14.5 percent. Therefore. the stretch which the yarn re ceives on the stepped roll is considerably less than the initial degree of overfeed. and the stretching serves mainly to stabilize the yarn without destroying its bulk and texture. The yarn is wrapped around guide 15 and passes to the larger diameter step of roll 17. The yarn is then wound on the larger step with the aid of guide 16 and passes over to guide rods 18 to traverse 19 where the yarn is wound at a tension of4 to 5 grams on dye spring 20 which is collapsible both radially and axially. The finished yarn package has a Shore hardness of 24 2 2 with a density of 240 grams per liter. The denier of the yarn as wound on the package is approximately 180 (200 d-tex). Yarn packages are then stacked axially in a dye device and are exposed to liquid dye which is heated from 60to 110C. at a rate of 1C. per minute and from 110 to 130C. at a rate of 2C. per minute. The optimum range for dye pickup for this yarn is 60 to 110C. The denier of the yarn after dyeing is about 200 (220 d-tex). The yarn shrinks about 11% during this process. The dye is held at 150 for at least 30 minutes. then the dye is pumped out of tank 26. the yarn packages are removed from dye rods 28 and are rinsed. Subsequently. the yarn is rewound onto cones and lubricated for knitting or weaving into fabrics. Waste loss during the present process is approximately 2 percent compared to approximately 10 percent for the process of the prior art.

What is claimed is:

1. In a continuous process for texturing then winding yarn on a package support that includes the steps of overfeeding a feed yarn through an air texturing jet with the resultant formation of texture-giving loops and winding the textured yarn on the package support under sufficient tension to stabilize the yarn without eliminating the loops and form a package of yarn, the improvement comprising: stretching the textured yarn between the texturing and winding steps. the degree of stretch being sufficient to stabilize the yarn without eliminating the loops; and winding the yarn under relatively low constant tension less than about 0.04 gram per denier to form a package of yarn suitable for package dyeing.

2. A process for dyeing a yarn package comprising the continuous steps of overfeeding a feed yarn through an air texturing jet with the resultant formation of texture-giving loops; stretching the textured yarn to stabilize the yarn without eliminating the loops; winding the textured yarn under relatively low constant tension less than about 0.04 gram per denier into a package on a collapsible package support to form a package of yarn; and the separate step of dyeing the package at an elevated temperature of from about 60C. to about C. 1k l= 

1. In a continuous process for texturing then winding yarn on a package support that includes the steps of overfeeding a feed yarn through an air texturing jet with the resultant formation of texture-giving loops and winding the textured yarn on the package support under sufficient tension to stabilize the yarn without eliminating the loops and form a package of yarn, the improvement comprising: stretching the textured yarn between the texturing and winding steps, the degree of stretch being sufficient to stabilize the yarn without eliminating the loops; and winding the yarn under relatively low constant tension less than about 0.04 gram per denier to form a package of yarn suitable for package dyeing.
 2. A process for dyeing a yarn package comprising the continuous steps of overfeeding a feed yarn through an air texturing jet with the resultant formation of texture-giving loops; stretching the textured yarn to stabilize the yarn without eliminating the loops; winding the textured yarn under relatively low constant tension less than about 0.04 gram per denier into a package on a collapsible package support to form a package of yarn; and the separate step of dyeing the package at an elevated temperature of from about 60*C. to about 130*C. 